Glossary:
B

The band or range of frequencies - often expressed in Hertz (Hz) for analogue devices and bits per second (bps) for digital ones - which can be transmitted through a communication system such as a computer or satellite network. Bandwidth is one measure of a system's information-carrying capacity: the wider the bandwidth, the more information that can be carried.

This CD/DVD lookalike won the high-definition DVD format battle - HD DVD was the loser – and is named after the colour of the laser needed to read the discs. Single layer Blu-ray discs can store up to 25GB of information (dual layer up to 50GB), which makes them ideal for HD films and programming.